This is a very good condition Mamiya 645 55mm f2.8 C lens, including both caps.
This lens has is cosmetically and optically mint but the iris is sticking on A auto. It works fine on M manual. Still very usable; you just need to stop down manually when using this lens. The price takes this into account.
Now seriously hard to find; this is still a really nice lens. If you want a better 55mm lens, I have a near mint 55mm N example in my other listings (as at 1 June 2026 anyway).